Mastering Astropy: Astronomical Data Cube Spaxels Spectra Continuum Fitting With Python |DESI ASTRO

In astronomy, data cubes are three-dimensional data arrays, with two dimensions corresponding to spatial coordinates (typically right ascension and declination) and the third dimension representing a spectral axis (often wavelength or frequency). These cubes contain rich information about the observed celestial object, including spatial distribution and spectral properties, allowing astronomers to study various physical characteristics.

Chapter Timestamps:
00:00:00 Introduction To Data Cube
00:04:47 Importing Libraries
00:06:13 Read FITS Data Cube
00:08:48 Extract Flux and Wavelength Data
00:13:10 Full Spaxel Spectra Extraction
00:20:00 Fit Continuum to Spaxel Spectra
00:04:36 Plotting All Fitted Continuum Spectra
00:27:55 Save All Fitted Spectra Into A Folder
00:35:15 Animate Fitted Continuum Spectra
00:37:00 Revising Code

Understanding Spaxels
A spaxel, or spatial pixel, refers to an individual element in the spatial dimensions of a data cube. Each spaxel contains a spectrum, providing a wealth of information about the object at that specific spatial location. Analyzing these spaxels is crucial for understanding astronomical objects' physical and chemical properties, such as galaxies or star-forming regions.

Load the Data Cube:

A data cube is a three-dimensional array where two dimensions correspond to spatial coordinates (like a grid of pixels) and the third dimension corresponds to different wavelengths or frequencies.
You load this data cube from a file, typically in FITS (Flexible Image Transport System) format, using Astropy. Astropy is a Python library that handles various types of astronomical data formats and operations.
Extract a Spectrum from a Spaxel:

A spaxel (spatial pixel) is a single point in the spatial grid of the data cube.
To analyze the spectrum at a specific spaxel, you select the corresponding spatial coordinates (e.g., x and y coordinates) from the data cube. This selection gives you a one-dimensional spectrum (flux values across different wavelengths) for that particular location.
Fit the Continuum:

The spectrum you have extracted typically contains both emission or absorption features and a smooth underlying continuum.
Continuum fitting involves modeling and subtracting this smooth, baseline component from the spectrum. This helps in identifying and analyzing the features more clearly.
SpecUtils provides tools for fitting this continuum. It uses mathematical models to estimate the baseline flux that represents the continuum.
Subtract the Continuum (Optional):

Once the continuum is fitted, you can subtract this baseline from the original spectrum. This removes the smooth background and highlights the features (like absorption lines or emission lines) more clearly.
The result is a spectrum where the continuum component has been removed, allowing for more focused analysis of the features.